(19)
(11) EP 1 176 390 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
27.11.2002 Bulletin 2002/48

(43) Date of publication A2:
30.01.2002 Bulletin 2002/05

(21) Application number: 01306120.5

(22) Date of filing: 17.07.2001
(51) International Patent Classification (IPC)7: G01C 17/38, G01C 17/28
(84) Designated Contracting States:
AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR
Designated Extension States:
AL LT LV MK RO SI

(30) Priority: 26.07.2000 JP 2000225368

(71) Applicant: Seiko Instruments Inc.
Chiba-shi, Chiba (JP)

(72) Inventor:
  • Kato, Kazuo
    Mihama-ku, Chiba-shi, Chiba (JP)

(74) Representative: Sturt, Clifford Mark et al
Miller Sturt Kenyon 9 John Street
London WC1N 2ES
London WC1N 2ES (GB)

   


(54) Method of adjusting drive current of magnetism sensor and electronic azimuth meter


(57) To reduce a dispersion in a sensitivity of a magnetism detecting circuit driving, by current, a magnetism sensor comprising magnetism resistance elements in a bridge constitution to a dispersion in a sensitivity of a magnetism sensor. An electronic azimuth meter is provided with EEPROM and drive current set values are previously stored to EEPROM. The drive current set values are calculated by a predetermined calculation by measuring bridge resistance of a magnetism sensor of the electronic azimuth meter. In detecting magnetism by the magnetism sensor, CPU controls a sensor drive circuit based on the drive current set values stored to EEPROM. Thereby, the sensor drive circuit supplies a magnetism sensor with optimum drive current in accordance with a bridge resistance value thereof.






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